In a Transmission Control Protocol/Internet Protocol (TCP/IP) transmission process, before new data is sent each time, it is needed to acknowledge whether the other side has received previous data, namely an ACK acknowledgement packet. However, in case of delay or low transmission rate, these ACK acknowledgement packets will be forced to delay to reach the destination. At this point, a data sending side has to waste a certain period of time to wait for receiving these ACK acknowledgement packets. Especially for a user of Digital Subscriber Line (DSL) and cable connection, when an uploading speed reaches a certain degree, uplink data is likely to slow or a downloading speed is obviously reduced, which is more serious especially for the user having a low uplink rate. This is because as an uplink is occupied completely, the acknowledgment of data will be delayed because of congestion of these uplink data.
With the development of a wireless terminal, e.g., a 4G wireless terminal, because its bandwidth is relatively wide, for making better use of bandwidths of uplink and downlink channels, a ratio of its bandwidths of uplink and downlink channels is usually greater than 1:2, even 1:9. So, when there is no any traffic shaping measure in the whole communication link, the downlink ACK acknowledge packet must be delayed, thereby the downlink channel is congested. FIG. 1 is a diagram of congestion of a downlink channel; as shown in FIG. 1, S101 is a downlink channel, and data types are: a data packet sent from a server normally and an uplink ACK acknowledge packet; S102 is an uplink channel, and data types are: a data packet sent from a client normally and a downlink ACK acknowledge packet. The two channels S101 and S102 are parallel; in the TCP/IP transmission process, before the new data is sent each time, it is needed to acknowledge whether the other side has received the previous data, so when the uplink channel reaches the limit of traffic capacity, namely there are more data packets to be sent in a buffer, a sending bandwidth cannot be provided for a new downlink ACK acknowledge packet, and then the data packets in the downlink channel will wait until a downlink ACK acknowledgement packet is received, thereby network congestion is caused.
The above situations can be collectively called a network with asymmetric uplink and downlink bandwidths. So far, in the general case, it is enabled to send more data once without need of immediate acknowledgement by increasing the capacity of TCP data packet. The main problem at the point is that: such a modifying way will cause a Ping value to stay at a high level (which causes a network lag phenomenon, commonly known as Lag), which is likely to cause serious consequences for the user browsing the Web, especially the user playing online games. For the data packet in which a TCP packet size is 512 k, it is so abnormal if the lag approaches 2 seconds. Generally speaking, only increasing the capacity of the TCP data packet cannot make the downloading speed reach a limit value of the bandwidth, and the situation that the sending of the ACK acknowledgement packet is delayed will not be improved better.